Lapping machine



Nov. 19, 1963 s. A. BOETTCHER LAPPING MACHINE 3 Sheets-Sheet 1 Filed Oct. 6, 1960 Sign/zen,

IN V EN TOR.

Nov. 19, 1963 s. A. BOETTCHER LAPPING MACHINE 3 Sheets-Sheet 2 Filed Oct. 6, 1960 Nov. 19, 1963 s. A. BOETTCHER LAPPING MACHINE Filed Oct. 6, 1960 s Sheets-Sheet s F I INVENTOR.

23 60 flig ahencLBoeii-cher United States Patent 3,110,988 LAPPIING MACHINE Stephen A. Boettcher, Evanston, 111., assignor to Speedlap Corporation, Skokie, 111., a corporation of Illinois Filed Oct. 6, 1960, Ser. No. 60,815 9 Claims. (Cl. 51-131) My invention relates to lapping machines for lapping flat surfaces and is directed to means for controlling the wear elfect of retaining and truing rings on the horizontal rotating lap surface for maintenance of its planar condition.

As is known, such rings, each resting in substantially fixed axis position on the lap surface to one side of the lap axis, serve the dual purposes of holding work pieces within them, against movement with the lap, and, by their base surfaces, of wearing the lap surface to keep it planar; the circular disk, presenting the lap surface, commonly referred to as the lap, is power-rotated at a selected constant speed, and the rings are free to rotate on their own axes, normally driven by the predominating friction area with the lap surface outwardly of their axes, and thus they wear the lap surface; and control of the speed of that induced rotation, relative to the rotational speed of the lap, can adjust that wear to restoring planar condition of the lap surface.

In United States Patent 2,912,799, issued November 17, 1959, I have set forth means for braking the rotation of weight plates fitting with close clearance within the rings and resting on work pieces in the rings.

The instant invention provides means for controlling the said wear eflect of the rings by driving them in reverse of normal direction at selected intervals for selected periods of time, both dictated by departure from planar condition of the lap.

My invention is illustrated in the accompanying drawings, wherein I have illustrated certain fundamentals, and

then, in detail, the features of my invention.

FIGURE 1 is an elevational view of the machine, with parts shown in vertical cross section taken on the plane of the main axis;

FIGURE 2 is a plan view taken on the plane of the line 2-2 of FIGURE 1;

FIGURE 3 is a vertical cross sectional view, on a larger scale, taken on the plane of the line 33 of FIG- URE 2; and

FIGURES 4 and 5 illustrate a modified form of the machine of my invention, in horizontal and axial crosssection, each indicated by the lines 44 and 55, respectively, on the other.

Referring firstly to FIGURES 1, 2 and 3:

The main support of the machine (see FIGURE 1) is a tubular housing 11, forming a pedestal, resting, by way of lugs 12, on base ring 13. The housing 11 has the access door 14.

Near its upper end, the housing 11 is provided with an inclined partition 15, welded at its periphery to the inner surface of the housing and serving the double purpose of supporting the collar 16 and forming a drip-pan as will be seen. The collar 16 has an internal flange 17 upon which a conventional gear reducer unit 18 is securely mounted by means of bolts 19. The output shaft 20 of the gear reducer unit :has keyed thereto a hub member 21, which, in turn, supports the wheel or plate 22, keyed thereto by the bolt 22', and which provides the lap surface above referred to. This lap wheel or plate 22 (see FIGURES l and 2) is a circular wear-resisting metallic alloy disc with a central well 23, leaving the annular lapping surface 24. A plurality of radial slots 25, 25 are cut downwardly from the lap surface to the depth of the well 23, in accordance with conventional practice, to

3,1 10,988 Patented Nov. 19, 1963 conduct mixture of fluid carrier and abrasive particles, fed to the lapping surface, for discharge to the drip-pan below.

Mounted within the housing 11 is a mount-plate 26 carried by a vertical shaft 27, set in brackets 28, 28, secured to the inside of the wall of the housing 11. The main drive motor 29 is carried on the mount-plate 26 by means of stud bolts 30, and the armature shaft 31 of said motor carries a sheave Wheel 32 which is operatively connected by a V-belt 33 with a sheave wheel 34 on the input shaft 35 of the gear reducer unit 18. Thus the lap 22 is driven by the motor 29. It may be driven in either direction, but let it be understood that it is driven in the direction of the arrow a (FIGURE 2).

Surrounding the lap 22 is a ring 36, upon which is mounted \a planar staging table 37, which has. notched out portions 38 (FIGURE 2) at its opposite sides for receiving the vertical channel columns 39, 39 mounted on opposite sides of housing 11. This staging table is supported from the housing 11 through the intervention of means (not shown) for slightly raising and lowering the table relatively to lap surface to facilitate loading and unloading work pieces to and from the lap; this means is subject to said Patent 2,912,799, and forms no part of the instant invention.

Mounted between the vertical channel columns 39, 39, above the lap, is a horizontal bridge member 40 provided with transverse arms 41, 41. At each end of each of these arms is a vertical bore for receiving a vertical spindle 42, there being thus four such spindles, as shown in FIGURE 2. Each of the spindles has a knurled upper end for manual grasping and a set screw 43 for holding in a vertically adjusted position. The lower end of each spindle takes into a balLbearing 44 in the center of a circular weight plate 45, the spindle thus serving to define the axis of rotation of such weight plate.

The weight plates, normally four being used as shown in FIGURE 2, for example, fit, with slight clearance, within the truing-retainer rings 46.

It will be noted, in FIGURE 1, for example, that work pieces, indicated at w, are placed within these rings, face to face on the lap, and then the weight plate 45 placed upon them. In operation, each truing-retainer ring, and the assembly of work pieces and weight plate contained thereby, by contact with the driven lap, rotate about the axis defined by the associated spindle, serving accurately to lap the lower surfaces of the work pieces and continuously to dress the lap surface.

Before proceeding with description of the specific means which I provide for control of this dressing of the lap surface, let it be understood that, at all times, in operation, there is feed of a mixture of a carrier and abrasive particles to the lap. As shovm in FIGURE 1, a tank 47 is suitably mounted within the housing 11, such tank constituting the immediate source of the said mixture. This tank has a filling inlet 48 and is covered by a plate 49 upon which is mounted a motor 50, for driving pumping means to impell the carrier, with abrasive particles in suspension, through discharge tube 51 which leads upwardly, conveniently through one of the columns 39, to spout 52 overhanging the lap surface 24, to which dripfeed of the mixture is thus accomplished; the used mixture gravitates to the drip-pan formed by the partition 15.

Reference will now be made also to FIGURE 3, which illustnates, on a larger scale and in further detail, ele ments of the novel means which I employ here.

It is well known that, with the lap 22 driven about its axis in the direction of the arrow a (FIGURE 2) each ring 46 will naturally and normally rotate in the direction of the direction of the arrows b (FIGURE 2), and so it is during most of the time of operation of my machine.

A horizontal circular friction drum 53 is mounted coaxially with the lap 22 and centrally of the group of rings 46, 46, each of which, as explained, is located on a fixed axis by way of weight plate 45 and spindle 42. This drurn comprises the circular friction member 54, of rubber or the like, having the central opening 54, and the metal top and bottom plates 54", 54", these plates being of lesser diameter than the friction member and also having central openings. A nut 55 rests on the bottom of the well bore 23 in the lap 24 and has the upwardly extending central tubular boss 56, which receives the threaded stem '57 extending downwardly from hand-knob 58 and threading into the base portion of the lap. 'I he friction member 53 is in frictional contact with the peripheral surfaces of all the rings 46, and the hand-knob can be turned to either of two positions, (a) to ieave the friction drum free to rotate, idly driven by the rings, or (b) to be rigidly connected with the lap, and thus drive the rings in the reverse direction.

It has been found that this reverse drive of the rings, applied at intervals and for brief periods of time, as may be necessary, functions to dress the lap surface, quickly and controllably, for the maintenance of its planar condition.

In FIGURES 4 and 5, which, as stated, illustrate a modified form of my invention, I drive the rings by gearing and I employ a dog clutch instead of a friction clutch.

The lap is shown at 22a and the truing-retainer rings, resting thereon, are shown at 46a, 46a, and their external cylindrical surfaces are formed throughout with gear teeth 46b, as shown and indicated, said gear teeth being elongated, as shown, to provide against the normal wear of the rings from the bottom.

An upwardly extending cylindrical stud 59 is axially fixed to the lap 22a by means of a downward extension 60 adjustably threaded into the lap and fixed by the lock nut '61. A pinion 62, corresponding in function to the friction drum 53 of FIGURE 3, is mounted on the stud 59, this by means of the loosely surrounding sleeve 63, secured on the pinion by cap screw 64 and having an internal shoulder 65, resting on the shoulder 66 of stud 59. The reduced upper end of the stud '59 extends, also with slight clearance, into the reduced bore at the upper end of the sleeve 63, the plane of the top surface of said extension being below the plane of the top surface of the sleeve.

A detent pin 67 is fixed, with press-fit, "in an axial bore in the top of the stud 59 and extends upwardly to receive a hand cap 68 having a central bore 69 fitting on the pin 67 with slight clearance. The lower end of the hand-cap 68 is counterbored to receive the upper end of the sleeve 63, as shown.

Mounted, by press fit, in the under side of the central portion of the hand-cap 68, on opposite sides of the bore 69, are two clutch pins 70, 70, which extend downwardly for entry into sockets 71, 71, formed half in the reduced upper end of the stud 59 and half in the upper end of the sleeve 63.

The hand-cap 68 is arranged for a limited vertical movement, determined by the two circumferential grooves 72a and 72b and the spring-pressed ball 73. The two pins 70, 70 enter the stud halves of the sockets when in the lowered position, ie when the ball is in the lower groove 72b, as shown in FIGURE 5, locking the pinion 62 to the lap, whereupon the rings are driven in direction in reverse of normal, as described in regard to FIGURES 1, 2. and 3. When the hand-cap is raised to its upper position, and the ball is in the upper groove 72a, the pinion is free to rotate, idly driven by the rings rotating in normal direction. This latter condition of course obtains when work is being performed. When corrective treatment of the lap surface appears to be in order, the driving motor 29 is stopped and the clutch is closed by lowering the hand cap. When the corrective treatment is completed, the hand cap is raised and the pinion 62 again idles.

I claim:

)1. In a lapping machine, a framework, 9. disk mounted on said framework on a vertical axis, means for rotating said disk, said disk having a horizontal planar lapping surface, a retaining and truing ring nesting on said lapping surface and normally rotatable in one direction about its own axis freely by its frictional contact with said lapping surface, applied driving means for rotating said ring about its axis in the opposite direction, and means for connecting and disconnecting said applied driving means.

2. In a lapping machine, a framework, a disk mounted on said framework on a vertical axis, means for rotating said disk, said disk having a horizontal planar lapping surface, a retaining and truing ring resting on said lapping surface and normally rotatable in one direction about its own axis freely by its frictional contact with said lapping surface, and means electively driven from said disk for rotating said ring about its axis in the opposite direction.

3. In a lapping machine, a framework, a disk mounted on said framework on a vertical axis, means for rotating said disk, said disk having a horizontal planar lapping surface, a retaining and truing ring resting on said lapping surface and normally rotatable in one direction about its own axis by its contact with said lapping surface, and a driven circular friction member engaging said ring for electively rotating said ring about its axis in the opposite direction.

4. In a lapping machine, a framework, a disk mounted on said framework on a vertical axis, means for rotating said disk, said disk having a horizontal planar lapping surface, a retaining and truing ring resting on said lapping surface and normally rotatable in one direction about its own axis by its contact with said lapping surface, a circular friction member engaging said ring, driving means for driving said friction member to rotate said ring about its axis in the opposite direction, and means for connecting and disconnecting said driving means to and from said friction member.

5. In a lapping machine, a framework, a disk mounted on said framework on a vertical axis, said disk having a horizontal planar lapping surface, a plurality of retaining and truing rings resting on said lapping surface, each normally rotatable about its own axis by its contact with said lapping surface, and a circular friction member disposed centrally of said rings and electively engageable with said rings for rotating them in the opposite direction.

6. In a lapping machine, a framework, a disk mounted on said framework on a vertical axis, means for rotating said disk, said disk having a horizontal p'lanar lapping surface, a retaining and truing ring resting on said lapping surface and normally rotatable in one direction about its own axis freely by its frictional contact with said lapping surface, said ring being formed with exteinal gear teeth, and a pinion meshing with said gear teeth for electively rotating said ring about its axis in the opposite direction.

7. In a lapping machine, a framework, a disk mounted on said framework on a vertical axis, means for rotating said disk, said disk having a horizontal planar lapping surface, a retaining and truing ring resting on said lapping surface and normally rotatable in one direction about its own axis freely by its frictional contact with said lapping surface, said ring being formed with external gear teeth, and a driven pinion meshing with said gear teeth for rotating said ring about its axis in the opposite direction, and means for connecting and disconnecting said pinion from the means for driving the same.

8. In a lapping machine, a framework, a disk mounted on said framework on a vertical axis, means for rotating said disk, said disk having a horizontal planar lapping surface, a retaining and truing ring resting on said lapping surface and normally rotatable in one direction about its own axis freely by its frictional contact with said lapping surface, said ring being formed with external gear teeth, a pinion meshing with said gear teeth, means for driving said pinion to rotate said ring about its axis in the opposite direction, and a dog clutch for connecting and disconnecting said driving means to and from said pinion.

9. In a lapping machine, a framework, a disk mounted on said framework on a vertical axis, means for rotating said disk, said disk having a horizontal planar lapping surface, a retaining and truing r-ing resting on said lapping surface and normally rotatable till one direction about its own axis freely by its frictional contact with said lapping surface, said ring being formed with external gear teeth, a pinion meshing with said gear teeth, means for driving said pinion to rotate said ring about its axis in the opposite direction, a dog clutch for connecting and 15 disconnecting said driving means to and from said pinion, said dog clutch having one element fixed centrally to said disk, and the other element fixed centrally to said pinion, and a hand cap for connecting and disconnecting said 5 elements.

References Cited in the file of this patent UNITED STATES PATENTS 2,740,237 Day et 'al. Apr. 3, 1956 2,839,877 Boettcher June 24, 1958 2,870,580 Norton Jan. 27, 1959 FOREIGN PATENTS 783,989 Great Britain Oct. 2, 1957 1,126,998 France Dec. 5, 1956 

1. IN A LAPPING MACHINE, A FRAMEWORK, A DISK MOUNTED ON SAID FRAMEWORK ON A VERTICAL AXIS, MEANS FOR ROTATING SAID DISK, SAID DISK HAVING A HORIZONTAL PLANAR LAPPING SURFACE, A RETAINING AND TRUING RING NESTING ON SAID LAPPING SURFACE AND NORMALLY ROTATABLE IN ONE DIRECTION ABOUT ITS OWN AXIS FREELY BY ITS FRICTIONAL CONTACT WITH SAID LAPPING SURFACE, APPLIED DRIVING MEANS FOR ROTATING SAID RING ABOUT ITS AXIS IN THE OPPOSITE DIRECTION, AND MEANS FOR CONNECTING AND DISCONNECTING SAID APPLIED DRIVING MEANS. 